1. Field of the Invention
This invention relates to well tools and more particularly to ported sliding sleeve devices for controlling fluid communication between flow conductors in wells.
2. Description of the Prior Art
Well tools having lateral ports through their walls to provide fluid communication between their interiors and the regions exterior thereof and controlled by sliding sleeve valves slidable therein between port-opening and port-closing positions have been used for many years to provide a fluid communication path between, for instance, the tubing and the surrounding annulus so that treating or loading fluids could be circulated through the well for such purposes as treating or killing the well, or the like.
Examples of such sliding devices and related tools are found in the following U.S. patents.
______________________________________ 2,947,363 3,115,188 3,292,706 2,999,546 3,211,232 3,871,450 3,051,243 3,244,234 ______________________________________
U.S. Pat. No. 2,947,363 issued Aug. 2, 1960 to T. H. Sackett et al. and discloses a ported sliding sleeve device in which the sliding sleeve valve is initially in port-open position to provide a passage through the wall of the device for the transfer of fluids between the interior of the pipe string to the exterior thereof. The sleeve valve is moved to closed position by dropping a ball or the like into the conduit and allowing it to come to rest on the sliding sleeve, after which the conduit is pressurized to force the ball and sliding sleeve down to closed position where it is held thereafter by a deformed washer engaging serrations on the sleeve's exterior surface. The bore of the sliding sleeve is necessarily restricted.
U.S. Pat. No. 2,999,546 issued Sept. 12, 1961 to G. G. Grimmer et al. and discloses a sliding sleeve device connected in a main flwo conductor and having a lateral opening connected to a smaller conductor or barrel extending alongside it. Its sliding sleeve is connected to a sliding valve in the smaller conduit. When the sliding sleeve is shifted, the sliding valve in the outer conduit is shifted. In this manner, flow through the lateral ports of both conduits is controlled. The sliding sleeve is shiftable by a tool lowered through the main flow conductor.
U.S. Pat. No. 3,051,243 issued Aug. 28, 1962 to G. G. Grimmer et al. and discloses a ported sliding sleeve device connectable in a well flow conductor. A sliding sleeve valve inside is shiftable between positions in which it either closes or opens the lateral ports in the wall of the body to either allow or prohibit the passage of fluids through the lateral ports as for circulation between the tubing and the casing. The sliding sleeve is shifted by use of a shifting tool lowered into the tubing, as on a wire line, in the manner shown and described in the patent and well known in the industry.
The device of the present invention is an improvement over the device of U.S. Pat. No. 3,051,243, and this patent, together with U.S. Pat. No. 3,211,232 next to be discussed, is believed by applicant to be the most pertinent prior art with which he is familiar.
U.S. Pat. No. 3,211,232 issued Oct. 12, 1965 to G. G. Grimmer and discloses a device like that covered by U.S. Pat. No. 3,051,243 just discussed but with added features. This sliding sleeve initially has its lateral ports closed by pump-out plugs 43 which can be expelled by applying a predetermined high pressure thereto through the tubing. The sliding sleeve is initially in open position, and a shifting device 130, 140 is locked therein. During completion of the well, the pump-out plugs prevent communication through the lateral ports so long as the pressure in the tubing does not exceed that exterior thereof by an appreciable amount. The pressure exterior of the tubing can be much higher than that inside without consequence since the pump-out plugs are supported against inward movement. When it is desired to circulate fluids through the lateral ports, the pressure in the tubing is increased until one or more of the pump-out plugs move outwardly, breaking the band or wire 48 which surrounds the device to retain these plugs in place. There are usually four of these plugs, but it has been common experience for less than the total number to be expelled because once one, or two, or three of them are expelled, the differential pressure may be so reduced that the remaining plug(s) cannot be expelled. Further, one or two of the pump-out plugs could be so close to the inner wall of the casing that they cannot be expelled. This could easily happen in crooked or deviated well bores where the tubing may lean against the wall of the surrounding casing. When it is desired to shift the sliding sleeve closed, a ball or plug is dropped down the tubing bore and allowed to settle atop the shifting device, thus plugging the bore through the shifting device. Pressure is then increased above the ball or plug, and the sleeve valve is forced down to closed position. The plug and shifting device are in this manner expelled and dropped to the bottom of the well. The pump-out plugs withstand considerable pressures from exterior of the tubing, but are responsive to and are expelled only by pressure within the tubing.
U.S. Pat. No. 3,244,234 issued to D. H. Flickinger on Apr. 5, 1966 and discloses a sliding sleeve device having a ported body and a sleeve controlling flow through the ports. In each of the two forms shown and described, the sleeve valve is moved to open position responsive to high exterior pressure. In one form the sleeve valve is inside the body and is spring biased toward closed position. In the other form, the sleeve valve surrounds the body. Both of these embodiments permit inward flow but prevent outward flow.
U.S. Pat. No. 3,292,706 issued to G. G. Grimmer et al. on Dec. 20, 1966 and discloses a well safety device utilizing a sliding sleeve device which admits annulus pressure to a safety valve mounted within the tubing. When the annulus pressure becomes excessive, the safety valve closes. The differential pressure which then develops across the closed safety valve in the tubing and moves the sliding sleeve valve to closed position to shut off communication from the annulus to the safety valve.
U.S. Pat. No. 3,871,450 issued to Marion B. Jett et al. on Mar. 18, 1975 and discloses a sliding sleeve device in which the sliding sleeve means surrounds dual side-by-side mandrels connectable to dual parallel tubing strings. A port in each mandrel communicates with a different variable-volume pressure chamber formed between the exterior of the mandrels and the interior of the sliding sleeve means. Pressuring one mandrel causes the sleeve to open the lateral flow ports and pressuring the other mandrel causes the sleeve to move to its closed position.
U.S. Pat. No. 3,115,188 issued Dec. 24, 1963 to C. B. Cochran et al. and discloses a sliding sleeve device and shifting tool therefor similar to that disclosed in U.S. Pat. No. 3,051,243 to Grimmer et al. discussed previously.
None of the prior art known to applicant shows a sliding sleeve device which can be installed in a well with its main sleeve valve in open position and has its lateral flow ports initially closed by means responsive to casing pressure but not to tubing pressure, and after the ports are opened by a predetermined high casing pressure, the closure is held in port-opening position.
The present invention overcomes at least some of the problems and shortcomings associated with ported well tools in which the ports are controlled by sliding sleeve valves which are shifted for the most part by shifting tools lowered thereto through the tubing. By providing a port closure responsive to casing pressure, high tubing pressures can be utilized in completing the well. Such a closure saves a trip into the well with a shifting tool and thus saves rig time and money. And, since the closure, once it is opened, is held in open position, it cannot at a later time interfere with flow through the flow ports. Further, since the port closure is inside the body, the casing wall cannot interfere with its operation. Additionally, the closure is protected during its trip into the well because it is completely enclosed within the body.